1. Field of the Invention
The present invention relates to an organic electroluminescent element in a display device panel using an organic emitting material.
2. Description of the Related Art
There is a conventional display element comprising an organic electroluminescent element (also referred to herein as an organic EL element) utilizing organic emitting materials as shown in FIG. 4. The organic EL element is a current injection type element in which the emitting efficiency of the element depends on the resistance values of the electrode and the connecting-line. In this case, when the resistance values of the electrode and the connecting-line are high, a large voltage drop occurs due to the flowing electric current therein, so that it results in unevenness of luminosity to reduce the display quality of the panel.
Therefore, it is necessary that a material having a low resistance value is used for the electrode and the connecting-line formed on the substrate. There is a problem of the high sheet resistivity of the transparent electrode of electric conductive material such as indium-tin oxide (ITO) which is generally used for the anode.
To overcome such a problem of the ITO anode, a metal film with a low resistivity (also referred to herein as a metal-bus-line) is used for the connecting-line between the electrodes of the same kind to decrease the line resistance value. In this case, after the anodes and the organic emitting material layers of the organic compound are patterned in turn on the substrate, the cathodes are patterned on the organic emitting material layers, and then the metal-bus-lines are patterned so as to connect between the ITO anodes on the substrate.
However, such a two-patterning process of the cathode and the metal-bus-line is so complicated. Therefore, the manufacture cost of the resultant display panel is apt to be high.